Introduction to dental implant

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DENTAL IMPLANTS
Guided by Prof ,Dr S. Mohan
Presented by Rince mohammed

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CONTENTS
 Introduction
 Osseointegration
 Classification of dental implants
 Implant components
 Treatment planning
 Surgical procedure
 Prosthetic phase
 Complications
 Conclusion

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INTRODUCTION
 Dental implant is an artificial titanium fixture which
is placed surgically into the jaw bone to substitute
for a missing tooth and its root(s).
 Dental implantology aims at functional and esthetic
rehabilitation of a patient affected by complete or
partial edentulism.

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OSSEOINTEGRATION
 A Swedish orthopedic surgeon, Prof Branemark, in
1952 accidentally discovered osseointegration.
 When pure Ti comes in contact with the living bone
tissue the two literally grow together to form a
permanent biological adhesion.
 Functional ankylosis- also called

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Factors for successful osseointegration.
 Biocompatible material- Ti, either commercially pure
or in certain alloys.
 Prrimary implant stability- it should be precisely
adapted to the prepared bony site
 Atraumatic surgery to minimize tissue damage
 An immobile, undisturbed healing phase.

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TITANIUM
 Biocompatibility is due to its surface oxide
 When exposed to air it forms a dense 4-nm layer of
Titanium dioxide TiO2 - chemically stable and very
corrosion-resistant.
 4 grades of commercially pure titanium-differing with
percentage of trace impurities in the metal.The
greater the contaminants the harder the metal.
 Grade 4 cpTi - commonly used for dental implants.

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 Grade 5 -Titanium alloy- Ti6Al4V.Offers equal
biocompatibility but better tensile strength and
fracture resistance than cpTi.
 Zirconia- similar in biocompatibility, improved
cosmetics, fracture resistance lower,can be used as
only one piece.

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STEPS OF OSSEOINTEGRATION
 Woven bone is quickly formed in the gap between the
implant and the bone.It has low biomechanical
capacity,- the occlusal load should be controlled
 After 1 to 2 months, under the effect of load, the
woven bone will slowly transform into lamellar bone

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IMPLANT TISSUE INTERFACE
 Implant and bone interface- The glycoprotein layer
on the bone is adsorbed on the implant surface with the
help of adhesive macromolecules like Fibronectin,
Laminin.
 They are bonded to the metallic oxide layer on the Ti
by covalent bonds, ionic bonds or van-der-walls
bonding.
 Implant connective tissue interface- gingival fibers
forms the attachement , is strong enough to withstand
the occlusal forces and microbial invasions.

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 Implant epithelial interface-Epithelium is
attached to implant surface through
hemidesomosomes and glycoproteins and considered
as Biologic seal.
 It forms a sulcus depth of 3 to 4 mm.

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CLASSIFICATION OF DENTAL
IMPLANTS
 Based on implant design

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Endosteal implants - A device which is placed into the
alveolar bone Transect only one cortical plate
 Blade/plate implant-thin plates in the form of blade
embedded into the bone

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 Ramus frame implant-Horse shoe shaped stainless
steel device. Inserted into the mandible from one
retromolar pad to the other and passes through the
anterior symphysis area

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 Root form implant - Designed to mimic the shape of
the tooth and for directional load distribution
 Forms:
 Cylinder
 Screw root form
 Combination

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SUBPERIOSTEAL (EPIOSTEAL) IMPLANT
 Placed directly beneath the periosteum overlying the
bony cortex,indicated in cases with inadequate bone
height for endosteal implants.

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 TRANSOSTEAL IMPLANT (Mandibular staple
implant)
 Penetrates both cortical plates
 It has subperiosteal and endosteal components.

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INTRAMUCOSAL IMPLANTS
 Inserted into the oral mucosa. Mucosa is used as
attachment site for the metal inserts of removable
dentures

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21.  Based on surgical timing
1. Immediate post-extraction implant.
2. Delayed immediate post-extraction implant. (2 weeks
to 3 months after extraction).
3. Late implantation (3 months or more after tooth
extraction).

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 According to the timing of loading of dental
implants
1. Immediate loading procedure.
2. Early loading (1 week to 12 weeks).
3. Delayed loading (over 3 months)

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IMPLANT COMPONENTS
1. Implant body
2. Healing screw
3. Healing abutment
4. Impression coping
5. Analogue or Implant Replica
6. Abutment
7. Prosthetic crown

24. Implant body
 The component that is
placed within the bone
during first stage of
surgery
 It could be threaded or
non threaded, with or
without a hydroxyapatite
coating

25. Healing screw (First stage
cover screw)
 It is placed into the top of the
implant to prevent bone ,soft
tissue or debris from invading
the abutment connection area
during healing.
 It facilitates suturing of the
soft tissue
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Healing abutment
 It is a temporary part placed on the
implant body to create a channel
through the mucosa while the
adjacent soft tissues heal and results
in a perimucosal seal around the
implant.
 Also called as permucosal extension
or gingival former.

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Impression coping (impression cap)
 It is used to transfer the position of the implant body or
the abutment to the working cast.
 The dentist screws the impression coping to the real
implant body and then takes an impression.
 The impression coping remain fixed in the impression
material and lab analogue is added prior to dispatching
to the lab.

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Analogue or Implant
Replica
 Analogues are used by lab
technicians to replicate
implants and their
position in a patient’s
mouth.
 A model of the patient’s
dentition is made using
an impression.

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Analogue provides a replica of the position of the implant
from which the technician can place and shape the
abutment and build the crown.

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Implant abutment
 Intermediate connector between
the implant and the restoration, it
may extend above the tissue.
 Supports or retains a prosthesis.
 4 types: cylindrical, shouldered,
angled and customizable
 Shouldered designs provide
natural-appearing emergence
profile

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TREATMENT PLANNING
Clinical evaluation
 Medical history
 Current dentoalveolar condition
 Local evaluation of site for implant placement -Alveolar bone
height, width, and jaw relationship and prosthetic restorability.
 Intraoral bone mapping - probe through the soft tissue to
assess the thickness of the soft tissues and measure the bone
dimensions at the proposed surgical site.
 Patient's expectations – Reasonable or not
 Oral hygiene status

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Radiographic evaluation
 2D- periapical, occlusal, panoramic, lateral
cephalometric radiographs.
 3D- CT,Tuned aperture computed tomography, cone-
beam CT, MRI

33. Study model analysis
 To determine
 Clinical length of the prosthetic crown that will be
supported by the implant. (Crown-implant ratio).
 Inter arch distance.
 The implant axis- it should be parallel to the axis of
adjacent natural teeth.
 Number and size of implants.

34. Surgical guides
 Helps to position the implants appropriately from the
prosthetic point of view.
 Holes are drilled into the acrylic at appropriate locations
with proper axis orientation.

35. Stereolithography
 From the available CT data a model can be created from a
solid block of material by means of a computer guided milling
device.
 Advantages:
 Precise evaluation of the actual osseous condition.
 Surgical therapy can be precisely planned preoperatively
for determination of the most favorable implant axis
orientation.
 Helpful for evaluating the relationship of mandible to
maxilla.

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FACTORS AFFECTING
TREATMENT
Implant position,Number,Size and design depends on
 Implant Prosthesis design- Implant supported denture,
over denture or FPD.
 Patient force factors- Para functional habits,
masticatory forces, Crown height,Occlusion.
 Bone density

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BONE EVALUATION
 Bone height - Minimum for long term survival is 10 mm It
is 12 mm in the posterior mandible because of nerve
proximity.
 Bone width - The minimal width should be 6 to 7 mm.
 Bone length -
 length refers to mesio distal distance
 1.5 mm from adjacent tooth & 3 mm from adjacent
implant, Should be 2 mm from adjacent anatomical
barrier.
 So a 5 mm implant requires atleast 8 mm length of the
bone

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 Bone angulation
 Ideally it is aligned with the forces of occlusion & is
parallel to the long axis of prosthodontic restoration.
 Premolar region-10°
 1 st Molar -15°
 2 nd Molar-20-25°
 For Wider ridge 30° is acceptable

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 Implant size
 Mand. Incisors and Max. LI=3-
3.5mm
 Max. anterior,PM of both arch
and Mand.Canine =4 mm.
 For all Molars =5-6mm
 The minimum amount of
interocclusal space required for
the restorative “stack” of implant
is 7 mm.

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 Crown : Implant
 Most ideal – 1 : 2
 More common – 1 : 1.5
 Minimum requirement – 1 : 1
 As the Crown : Implant increases the number of implants
& / or wider implants should be inserted to counteract the
increase in stress.

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Bone density
 For softer bone, number and diameter of implant must
be increased with more and deeper threads.
 Bone density can be assesed by Misch classification on
bone density (1988) from C.T using Hounsfield Units
or C.T number.
 He classified it in to 4 groups D1 to D4. and D5 is
immature bone.
 Higher the CT number, denser is the tissue.
 D1: > 1250 HU; D2: 850 to 1250 HU; D3: 350 to 850
HU; D4: 150 to 350 HU; and D5: < 150 HU.

42. Misch classification on bone density(1988)
D5 Immature, nonmineralized bone

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 Surgery can be done in one stage or in two stage.
 2 stage surgery-In first stage implants are surgically
placed under the gum and the patient is made to wait
for 6 months for osseointegration
 2nd stage surgery is then performed where the healing
gingival former is placed and after a week of satisfactory
formation of a gingival collar for emergence profile is
achieved, impressions are made for implant prosthesis,
which may be cemented or screw retained
 one-stage surgery –Implant is placed and left exposed
through the gum. In this case, a second stage surgery in
not needed
SURGICAL PROCEDURE

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Preoperative care
 Surgical site preparation and isolation
 Preoperative antibiotic prophylaxis - oral dose of 2
g penicillin V 1 hour before
 Local anesthesia
 Incision- Mid crestal incision with a margin of
1.5mm keratinized tissue buccally extending to the
sulcus of adjacent teeth
 Flap should be reflected and elevated.

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Implant osteotomy
 After the bone is exposed the surgical guide template
is positioned.It directs the angulation of the implant.
 A low-speed (1500-2000[rpm]),high-torque handpiece
and copious irrigation are necessary to prevent excess
thermal injury to the bone

46. Irrigation :
 keeps the local bone
temperature at normal body
temperature and also to flush
out the bone debris from drill
hole.
 NS at room temperature is
ideal.

47.  Various types of physiodispensers are available which
can controll speed,torque,and irrigation.

48. Bone Drilling
 The manufacturers give a guide to the
sequence of drill(Sizes) to be used in
order to make proper sized drill hole for
a particular implant
 The drills are marked for depth to guide
the surgeon.
 Drills are used in ascending order of
diameter.
 Recommended drilling speed- < 800 rpm

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 With the initial drill, the center of the implant
recipient site is marked and the initial pilot hole is
prepared
 A paralleling pin is placed in the initial preparation to
check alignment and angulation .
 If it is appropriate,drill hole is sequentially enlarged to
dimensions of the implant.
 After the desired depth and diameter of the recipient
site is accomplished, the implant can be placed.

50. Implant placement
 After final osteotomy, the site is lavaged and aspirated
to remove debris and blood.
 For Ti implants, an uncontaminated surface oxide
layer is necessary to obtain osseointegration.So
touching with gloves, soft tissue or a dissimilar metal
should be avoided.
 The implant is rotated with 30 rpm by low speed high
torque hand piece /hand ratchet.
 It should be rigid with no mobility on slight
compression

51.  Post insertion radiograph- to evaluate the position ,
adjacent vital structure.
 Cover screw is inserted. Flaps are sutured.
 If implant position is not correct,it may be removed
and reinserted after several months later.

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 Second stage surgery
 In second stage surgery in prefferably a ‘+’ shaped
incision is made in the overlying mucosa and the
cover screw is exposed and removed with a Hex
Driver, and is replaced with a gingival former and
is left for 7 to 17 days
 The gingival former helps in formation of a
gingival collar around the future abutment which
helps in giving the final prosthesis a more natural
appearance.

53. PROSTHETIC PHASE
Impression :
 After the healing period,gingival former is
removed,impression copings are put onto the implant
and impression is taken by open/closed technique.
 The implant analogue is fixed on the impression coping
and the impression is poured in die stone.
 Now the analogue is seated in die with same
angulation as in bone.
 Once the plaster is set the the coping is removed and
abutments are placed over the lab analogue.
 Then the crown is fabricated over the abutment.

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 After the fabrication of prosthesis, the abutment is
taken off the cast leaving the implant analogue in
the cast.
 This abutment can now be transferred and screwed
onto the implant and prosthesis affixed to it (either
screwed or cemented to the abutment)
 Occlusal adjustments are undertaken if required

55. COMPLICATIONS
 Intraoperative
 Flap tear
 Insufficient irrigation
 Perforation of buccal or lingual cortex
 Inferior alveolar nerve injury
 Implant/Drill impinges on adjacent tooth root
 Perforation of maxillary sinus
 Perforation of pyriform fossa base
 Lack of primary stability of implants
 Fracture of implant

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 Immediate postoperative
 Swelling
 Nerve injuries
 Pain(unusual)
 Haemorrhage(Rare)
 Delayed
 Infection
 Secondary Haemorhhage
 Nerve injury
 Loosening of implant
 Implant Exposure

57. Implant failure
 Mobility of implant during healing period
 Pain , infection
 Radiolucency around implant.
 whatever the cause,the implant should be removed.
 Grafting and reinsertion can be done after 8-10wks.

58. COMPLEMENTARY PROCEDURES
 Bone grafting for implants- Done when the bone is
too narrow or too short to place an adequate sized
implant.
Sinus lift
 Our sinuses are located in close proximity to the upper
posterior jaw bone. In some cases, the sinus floor
"dips" down, causing that area to lose bone height,then
a "sinus lift" procedure is necessary in order to
increase bone height.

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 A cortical window 2 to 3 mm above the sinus floor
is created with round bur down to the membrane
of the sinus.
 Careful in-fracture of the window with dissection
of the sinus membrane off the sinus floor creates
the space necessary for graft placement; the
 Corticocancellous blocks may be placed in the
resulting defect.

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61. CONCLUSION
 Dental implants have overall had high success rates,
but their placement and restoration still have the
boundaries of both biomedical science and art.
 The effectiveness of different designs of implant-
supported prostheses as well as associated treatment
modalities leads to improvement in speech, function
and quality of life.